1. Field of the Invention
The invention relates to a heat exchanger of the tube bank type, in particular for automotive vehicles or automobiles, in which the tube ends are mounted in fluid-tight manner within the holes of a header or a tube sheet.
2. Description of the Prior Art
In heat exchangers of this type, the tube ends are usually flared outwards from the header in order to form an abutment shoulder for retaining the tubes within the holes of the header in a predetermined direction of displacement of the header along the longitudinal axis of the tubes corresponding to detachment of the header under the action of the internal pressure which prevails within the heat exchanger under service conditions.
This mode of assembly of the tubes within the headers therefore makes it possible to maintain the header on the tubes in a predetermined direction with respect to the longitudinal axis of the tubes, the header being maintained in the opposite direction by applying the tubes of the tube bank against the fins.
As a general rule, the tubes are fitted with flat and parallel fins through which the tubes pass at right angles, said fins being secured to said tubes by crimping, for example. During assembly of the heat exchanger, the header is applied against the end fins of the tube bank, thus producing compression of the fins which are then in contact with each other at the end of the tube bank. As a result of this compression of the end fins of the tube bank, it is difficult to obtain an accurately defined spatial interval between the two headers. This is liable to have an adverse effect on the operations which consist in mounting and attaching the heat exchanger within the engine of an automotive vehicle since the headers and/or the water boxes mounted on these headers are often provided with locating studs or means for engaging or fastening the heat exchanger on a stationary chassis or frame.
Furthermore, fins which have been compressed against each other at the ends of the tube bank no longer serve any useful purpose from the point of view of heat exchange between the fluid which circulates within the heat exchanger and the fluid which flows through the tube bank and sweeps the tube fins.